#include <stdint.h>
#include <memory.h>
#include <math.h>

#ifndef _DES_COMMON_H
#define _DES_COMMON_H
const uint8_t const IPtable[64] = {58,50,42,34,26,18,10,2,
                                   60,52,44,36,28,20,12,4,
                                   62,54,46,38,30,22,14,6,
                                   64,56,48,40,32,24,16,8,
                                   57,49,41,33,25,17,9,1,
                                   59,51,43,35,27,19,11,3,
                                   61,53,45,37,29,21,13,5,
                                   63,55,47,39,31,23,15,7};

const uint8_t const RIPtable[64] = {40,8,48,16,56,24,64,32,
                                    39,7,47,15,55,23,63,31,
                                    38,6,46,14,54,22,62,30,
                                    37,5,45,13,53,21,61,29,
                                    36,4,44,12,52,20,60,28,
                                    35,3,43,11,51,19,59,27,
                                    34,2,42,10,50,18,58,26,
                                    33,1,41,9,49,17,57,25};


const uint8_t const Etable[48] = {32,1,2,3,4,5,
                                  4,5,6,7,8,9,
                                  8,9,10,11,12,13,
                                  12,13,14,15,16,17,
                                  16,17,18,19,20,21,
                                  20,21,22,23,24,25,
                                  24,25,26,27,28,29,
                                  28,29,30,31,32,1};

const uint8_t const S[8][4][16] = {{{14,4,13,1,2,15,11,8,3,10,6,12,5,9,0,7},
                                    {0,15,7,4,14,2,13,1,10,6,12,11,9,5,3,8},
			            {4,1,14,8,13,6,2,11,15,12,9,7,3,10,5,0},
			            {15,12,8,2,4,9,1,7,5,11,3,14,10,0,6,13}
                                   },

                                   {{15,1,8,14,6,11,3,4,9,7,2,13,12,0,5,10},
			            {3,13,4,7,15,2,8,14,12,0,1,10,6,9,11,5},
			            {0,14,7,11,10,4,13,1,5,8,12,6,9,3,2,15},
			            {13,8,10,1,3,15,4,2,11,6,7,12,0,5,14,9}
			           },

                                   {{10,0,9,14,6,3,15,5,1,13,12,7,11,4,2,8},
		                    {13,7,0,9,3,4,6,10,2,8,5,14,12,11,15,1},
			            {13,6,4,9,8,15,3,0,11,1,2,12,5,10,14,7},
			            {1,10,13,0,6,9,8,7,4,15,14,3,11,5,2,12}
			           },

                                   {{7,13,14,3,0,6,9,10,1,2,8,5,11,12,4,15},
		                    {13,8,11,5,6,15,0,3,4,7,2,12,1,10,14,9},
			            {10,6,9,0,12,11,7,13,15,1,3,14,5,2,8,4},
			            {3,15,0,6,10,1,13,8,9,4,5,11,12,7,2,14}
			           },

                                   {{2,12,4,1,7,10,11,6,8,5,3,15,13,0,14,9},
		                    {14,11,2,12,4,7,13,1,5,0,15,10,3,9,8,6},
			            {4,2,1,11,10,13,7,8,15,9,12,5,6,3,0,14},
			            {11,8,12,7,1,14,2,13,6,15,0,9,10,4,5,3}
			           },
  
                                   {{12,1,10,15,9,2,6,8,0,13,3,4,14,7,5,11},
		                    {10,15,4,2,7,12,9,5,6,1,13,14,0,11,3,8},
			            {9,14,15,5,2,8,12,3,7,0,4,10,1,13,11,6},
			            {4,3,2,12,9,5,15,10,11,14,1,7,6,0,8,13}
			           },

                                   {{4,11,2,14,15,0,8,13,3,12,9,7,5,10,6,1},
		                    {13,0,11,7,4,9,1,10,14,3,5,12,2,15,8,6},
			            {1,4,11,13,12,3,7,14,10,15,6,8,0,5,9,2},
			            {6,11,13,8,1,4,10,7,9,5,0,15,14,2,3,12}
			           },
 
                                   {{13,2,8,4,6,15,11,1,10,9,3,14,5,0,12,7},
		                    {1,15,13,8,10,3,7,4,12,5,6,11,0,14,9,2},
			            {7,11,4,1,9,12,14,2,0,6,10,13,15,3,5,8},
			            {2,1,14,7,4,10,8,13,15,12,9,0,3,5,6,11}
			           }
                                  };

const uint8_t Ptable[32] = {16,7,20,21,
			    29,12,28,17,
                            1,15,23,26,
                            5,18,31,10,
                            2,8,24,14,
                            32,27,3,9,
                            19,13,30,6,
                            22,11,4,25};


static inline void setBit(uint8_t *dst, int bit, int loc)
{
	int i, j;
	uint8_t mask;
		
	i = floor(loc / 8);
	j = loc % 8;
	
	switch(bit)
	{
		case 0:
			mask    = ~(1U << j);
			dst[i] &= mask;
			break;

		case 1:
			mask    = 1U << j;
			dst[i] |= mask;
			break;

		default:
			break;
	}
}

static inline void getBit(uint8_t *src, int *bit, int loc)
{
	int i, j;
	uint8_t mask;

	i = floor(loc / 8);
	j = loc % 8;

	mask = 1U << j;
	*bit = (src[i] & mask) >> j;
}
#endif

static inline void makeByte(uint8_t *ch, uint8_t *output)
{
	int sum = 0;
	int i;
	uint8_t newch = *ch;
	uint8_t mask = 1;

	for(i = 0; i< 7; i ++)
	{
		sum ^= ((newch) & mask);
		newch >>= 1;
	}
	
	switch(sum)
	{
		case 0:
			*ch &= 0x7f;
			break;
		case 1:
			*ch |= 0x80;
			break;
		default:
			break;
	}

	memcpy(output, ch, 1);

}

static inline void calcFValue(uint8_t *data, uint8_t *key, uint8_t *ans)
{
	int i, loc, bit, j, loc1;
	int tbit, kbit;
	int row, col, rt;
	uint8_t temp[6];
	uint8_t temp1[4];
	uint8_t temp2[4];

	for(i = 0; i < 48; i ++)
	{
		loc = Etable[i] - 1;
		getBit(data, &bit, loc);
		setBit(temp, bit, i);
	}

	loc = 0;
	loc1= 0;
	for(i = 0; i < 8; i ++)
	{
		row = 0;
		col = 0;

		getBit(temp, &tbit, loc+5);
		getBit(key, &kbit, loc+5);
		bit = (tbit ^ kbit) << 1;

		row += bit;

		getBit(temp, &tbit, loc);
		getBit(key, &kbit, loc);
		bit = tbit ^ kbit;

		row += bit;

		for(j = 4; j >= 1; j --)
		{
			col <<= 1;
			getBit(temp, &tbit, loc + j);
			getBit(key, &kbit, loc + j);
			bit = tbit ^ kbit;

			col += bit;
		}
		
		rt = S[i][row][col];
		for(j = 3; j >= 0; j --)
		{
			bit = rt % 2;
			setBit(temp1, bit, loc1 + j);
			rt >>= 1;
		}

		loc += 6;
		loc1+= 4;
	}

	for(i = 0; i < 32; i ++)
	{
		loc = Ptable[i] - 1;
		getBit(temp1, &bit, loc);
		setBit(temp2, bit, i);
	}

	memcpy(ans, temp2, 4);
}
